Re: Imitation is the sincerest form of flattery

[Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>]

On Wed, 26 Mar 2003 10:06:41 -0500, Hyman Rosen <hyrosen@mail.com>
wrote:

>Dmitry A. Kazakov wrote:
>> Wrong for what? There is no other way to specify a type set other than
>> through closures of a subtyping relation. That's what inheritance is
>> about.
>
>Yes there is. We've been through all this before.
>The other way is through use patterns.

Pattern is not a language term. So it cannot be an other way. Other
way is cut'n'paste and patterns is a manual how to do it.

>> Let you declare:
>>    void Foo (Element& X);
>> then A[i] have to be of Element type to allow substitutability:
>> 
>>    Foo (A [i]);
>> If A [i] is of some proxy class then you need ether to make the class
>> a subtype of Element, or to write a wrapper for Foo.
>
>No, you declare
>     template <typename Element> void Foo(Element &X);
>and you just call
>     Foo(A[i]);

Exactly what I meant. It is no more a normal subroutine taking Element
a parameter. All users of my array have to know that it is not an
array; that they cannot index it is a normal way; that they have to
review and redesign all the code working with the type Element if
there is an array built on Element. Excellent.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de